Structural hardening mechanisms of lead-cadmium-silver alloys for battery's grids.

The reequilibration of supersatured Pb-Cd-Ag alloys was studied by several experimental methods: hardness measurements, optical and electron microscop y, electron microprobe. Two structural states were considered: as-cast allo y, rehomogenised alloy. Lead-cadmium-silver alloys with 2 or 3.2 weight% Cd and 0.07, 0.15 or 0.3 weight% Ag were studied. The explored temperatures w ere 20, 80 and 100 degrees C. Globally, a small addition of silver results in an increase in hardness. For the Pb 3.2%Cd 0.15%Ag alloy, the microstruc ture is charcterized by the formation of coarse Ag5Cd8 cristals during sold ification. With an increase in the Ag level in the Pb 2%Cd X%Ag (X = 0.07, 0.15, 0.3) the quantity of eutectic increases.